Machining data

Machining data

Some general points can be made about machining. Plastics are very poor thermal conductors. Any heat build-up must be avoided, as it will not dissipate, and will cause deformation, build or release mechanical stress, can lead to discoloration and local melting.

Thus, use very sharp tools with clearance to avoid rubbing, generally use high feed rate. Good swarfing should be carrying the heat away. Drilling should be made in steps, swarf continuously removed, and the hole cooled. When machining with coolants and lubricants, the chemical resistance of the plastic must be considered, so as to avoid any stress-cracking.

For unfilled materials, normal high speed steel can be used. When working in fibre reinforced materials, use hardened steel or better. Some materials require diamond egde tools, and even post-tempering of the material.